In-Situ and On-Line Monitoring and Control of Biotechnological Processes. The advantages of in situ and on-line monitoring of biological production processes are demonstrated by four examples : production of baker’s yeast, maunufacturing of alkaline protease by B. licheniformis, formation of intracellular fusion protein by recombinant E. coli, and production of antibiotica by ascomycetes and streptomycetes.